A facile and rapid microwave irradiation method was developed to prepare ZnS nano-particles (NPs) using a set of ionic liquids (ILs) based on the bis(trifluoromethylsulfonyl)
imide anion and different cations of 1-alkyl-3-methyl-imidazolium. The phases, structures,
and optical absorption properties of the NPs were determined in depth with X-ray powder
diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, UV–vis
absorption spectroscopy (UV–vis), diffuse reflectance spectroscopy (DRS), and photolumi-nescence spectroscopy (PL). The average crystallite size of the ZnS NPs calculated from the
XRD pattern was of the order of 2.8 nm which exhibits cubic zinc blende structure. The
energy band gap measurements of NPs were carried out by UV and DRS. The results
revealed that the ZnS NPs exhibit strong quantum confinement effect. The optical band gap
energy increases significantly compared with those of the bulk ZnS. The refractive indices
for different ZnS nanosamples and different concentrations of ZnS NPs for a typical sample
suspended in deionized water were also measured.
&